| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.base.io; |
| 17 | |
| 18 | import org.qedeq.base.utility.Splitter; |
| 19 | import org.qedeq.base.utility.StringUtility; |
| 20 | |
| 21 | |
| 22 | /** |
| 23 | * Wraps a text output stream. |
| 24 | * |
| 25 | * @author Michael Meyling |
| 26 | */ |
| 27 | public abstract class AbstractOutput { |
| 28 | |
| 29 | /** Tab level. */ |
| 30 | private StringBuffer spaces = new StringBuffer(); |
| 31 | |
| 32 | /** Break at this column if greater zero. */ |
| 33 | private int breakAt; |
| 34 | |
| 35 | /** Tab level of current line. This is equal to spaces before any character is |
| 36 | * written. After writing to the current line this value is fixed and doesn't change even |
| 37 | * if the tab level is changed. |
| 38 | */ |
| 39 | private String spacesForCurrentLine = ""; |
| 40 | |
| 41 | /** Current column. */ |
| 42 | private int col; |
| 43 | |
| 44 | /** Token buffer. */ |
| 45 | private StringBuffer tokenBuffer = new StringBuffer(); |
| 46 | |
| 47 | /** Whitespace buffer. */ |
| 48 | private StringBuffer wsBuffer = new StringBuffer(); |
| 49 | |
| 50 | /** |
| 51 | * Constructor. |
| 52 | */ |
| 53 | public AbstractOutput() { |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Add whitespace to output. |
| 58 | * |
| 59 | * @param ws Add this whitespace. |
| 60 | */ |
| 61 | public void addWs(final String ws) { |
| 62 | final String[] lines = StringUtility.split(ws, "\n"); |
| 63 | for (int i = 0; i < lines.length; i++) { |
| 64 | if (i > 0) { |
| 65 | println(); |
| 66 | } |
| 67 | addWsWithoutCR(lines[i]); |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Add whitespace to output. Must not contain CRs. |
| 73 | * |
| 74 | * @param ws Add this whitespace. |
| 75 | */ |
| 76 | private void addWsWithoutCR(final String ws) { |
| 77 | if (tokenBuffer.length() > 0) { |
| 78 | if (fits(wsBuffer.length() + tokenBuffer.length())) { |
| 79 | if (col == 0) { |
| 80 | appendSpaces(); |
| 81 | } |
| 82 | append(wsBuffer.toString()); |
| 83 | col += wsBuffer.length(); |
| 84 | append(tokenBuffer.toString()); |
| 85 | col += tokenBuffer.length(); |
| 86 | } else { |
| 87 | // forget non fitting part of white space |
| 88 | if (col != 0) { |
| 89 | appendFittingPart(wsBuffer.toString()); |
| 90 | append("\n"); |
| 91 | } |
| 92 | col = 0; |
| 93 | appendSpaces(); |
| 94 | append(tokenBuffer.toString()); |
| 95 | col += tokenBuffer.length(); |
| 96 | } |
| 97 | wsBuffer.setLength(0); |
| 98 | tokenBuffer.setLength(0); |
| 99 | } |
| 100 | wsBuffer.append(ws); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Append token to output. |
| 105 | * |
| 106 | * @param part Add this part. |
| 107 | */ |
| 108 | public void addToken(final String part) { |
| 109 | // remember tabular spaces when we start writing |
| 110 | if (col == 0 && part.length() > 0) { |
| 111 | setTabLevel(); |
| 112 | } |
| 113 | tokenBuffer.append(part); |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Flush output. |
| 118 | */ |
| 119 | public void flush() { |
| 120 | addWsWithoutCR(""); |
| 121 | appendFittingPart(wsBuffer.toString()); |
| 122 | wsBuffer.setLength(0); |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Append a part of given text so that the current maximum column is not exceeded. |
| 127 | * |
| 128 | * @param txt Write this text. |
| 129 | * @return Length of written characters. |
| 130 | */ |
| 131 | private int appendFittingPart(final String txt) { |
| 132 | final int columnsLeft = columnsLeft(); |
| 133 | if (columnsLeft > 0) { |
| 134 | final String part = StringUtility.substring(txt, 0, columnsLeft); |
| 135 | append(part); |
| 136 | col += part.length(); |
| 137 | return part.length(); |
| 138 | } else if (columnsLeft < 0) { |
| 139 | append(txt); |
| 140 | col += txt.length(); |
| 141 | return txt.length(); |
| 142 | } |
| 143 | return 0; |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Print character to output. |
| 148 | * |
| 149 | * @param c Append this. |
| 150 | */ |
| 151 | public void print(final char c) { |
| 152 | print("" + c); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Print text and split at white space if text doesn't fit within maximum column size. |
| 157 | * Also flushes output. |
| 158 | * |
| 159 | * @param text Append this. |
| 160 | */ |
| 161 | public void print(final String text) { |
| 162 | flush(); |
| 163 | if (text == null) { |
| 164 | addToken("null"); |
| 165 | } else { |
| 166 | final String[] lines = StringUtility.split(text, "\n"); |
| 167 | for (int i = 0; i < lines.length; i++) { |
| 168 | final Splitter split = new Splitter(lines[i]); |
| 169 | while (split.hasNext()) { |
| 170 | final String token = split.nextToken(); |
| 171 | final boolean isWhitespace = token.trim().length() == 0; |
| 172 | if (isWhitespace) { |
| 173 | addWsWithoutCR(token); |
| 174 | } else { |
| 175 | addToken(token); |
| 176 | } |
| 177 | } |
| 178 | if (i + 1 < lines.length) { |
| 179 | println(); |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | flush(); |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Append text directly to output device. |
| 188 | * |
| 189 | * @param text Append this text. |
| 190 | */ |
| 191 | public abstract void append(final String text); |
| 192 | |
| 193 | /** |
| 194 | * Get writing position. |
| 195 | * |
| 196 | * @return Writing position. |
| 197 | */ |
| 198 | public abstract long getPosition(); |
| 199 | |
| 200 | /** |
| 201 | * Print spaces and text to output. |
| 202 | * |
| 203 | * @param text Append this. |
| 204 | */ |
| 205 | public void printWithoutSplit(final String text) { |
| 206 | flush(); |
| 207 | if (text == null) { |
| 208 | return; |
| 209 | } |
| 210 | if (col == 0) { |
| 211 | if (text.length() > 0) { |
| 212 | // remember tabular spaces when we start writing |
| 213 | setTabLevel(); |
| 214 | appendSpaces(); |
| 215 | } |
| 216 | } else if (!fits(text)) { |
| 217 | println(); |
| 218 | appendSpaces(); |
| 219 | } |
| 220 | append(text); |
| 221 | col += text.length(); |
| 222 | } |
| 223 | |
| 224 | /** |
| 225 | * Does the text fit to current line? |
| 226 | * |
| 227 | * @param text Check if this text could be appended without line break. |
| 228 | * @return Does it fit? |
| 229 | */ |
| 230 | private boolean fits(final String text) { |
| 231 | if (text == null) { |
| 232 | return true; |
| 233 | } |
| 234 | return fits(text.length()); |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * Does a text with given length fit to current line? |
| 239 | * TODO 20110104 m31: should't we use spacesForCurrentLine also? |
| 240 | * |
| 241 | * @param length Check if a text of this length could be appended without line break. |
| 242 | * @return Does it fit? |
| 243 | */ |
| 244 | private boolean fits(final int length) { |
| 245 | return breakAt <= 0 || col + length <= breakAt; |
| 246 | } |
| 247 | |
| 248 | /** |
| 249 | * How many columns have we left? |
| 250 | * |
| 251 | * @return Columns left. Returns -1 if there is no limit. |
| 252 | */ |
| 253 | public int columnsLeft() { |
| 254 | if (breakAt <= 0) { |
| 255 | return -1; |
| 256 | } else { |
| 257 | return Math.max(0, breakAt - col); |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | /** |
| 262 | * Print object to output. |
| 263 | * |
| 264 | * @param object Append text representation of this. |
| 265 | */ |
| 266 | public void print(final Object object) { |
| 267 | print(String.valueOf(object)); |
| 268 | } |
| 269 | |
| 270 | /** |
| 271 | * Print spaces text and new line to output. |
| 272 | * |
| 273 | * @param token Append this. |
| 274 | */ |
| 275 | public final void println(final String token) { |
| 276 | print(token); |
| 277 | println(); |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Print object and new line to output. |
| 282 | * |
| 283 | * @param object Append text representation of this. |
| 284 | */ |
| 285 | public final void println(final Object object) { |
| 286 | println(String.valueOf(object)); |
| 287 | } |
| 288 | |
| 289 | /** |
| 290 | * Print new line to output. |
| 291 | */ |
| 292 | public void println() { |
| 293 | flush(); |
| 294 | if (col == 0 && spaces.toString().trim().length() > 0) { |
| 295 | setTabLevel(); |
| 296 | appendSpaces(); |
| 297 | } |
| 298 | append("\n"); |
| 299 | col = 0; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Skip until given column. To do this we append spaces. |
| 304 | * |
| 305 | * @param column Skip to this column. |
| 306 | */ |
| 307 | public void skipToColumn(final int column) { |
| 308 | for (int i = col; i < column; i++) { |
| 309 | printWithoutSplit(" "); |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | /** |
| 314 | * Reset tab level to zero. |
| 315 | */ |
| 316 | public final void clearLevel() { |
| 317 | // flush(); |
| 318 | spaces.setLength(0); |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Decrement tab level. |
| 323 | */ |
| 324 | public final void popLevel() { |
| 325 | if (spaces.length() > 0) { |
| 326 | spaces.setLength(spaces.length() - 2); |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * Decrement tab level. |
| 332 | * |
| 333 | * @param characters Number of characters to reduce from tab level. |
| 334 | */ |
| 335 | public final void popLevel(final int characters) { |
| 336 | if (spaces.length() > 0) { |
| 337 | spaces.setLength(Math.max(spaces.length() - characters, 0)); |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | /** |
| 342 | * Return current tab string. |
| 343 | * |
| 344 | * @return Current tab string. |
| 345 | */ |
| 346 | public final String getLevel() { |
| 347 | return spaces.toString(); |
| 348 | } |
| 349 | |
| 350 | /** |
| 351 | * Set current tab string. |
| 352 | * |
| 353 | * @param level Tab string. |
| 354 | */ |
| 355 | public final void setLevel(final String level) { |
| 356 | spaces.setLength(0); |
| 357 | spaces.append(level); |
| 358 | } |
| 359 | |
| 360 | /** |
| 361 | * Increment tab level (this are two spaces). |
| 362 | */ |
| 363 | public final void pushLevel() { |
| 364 | spaces.append(" "); |
| 365 | } |
| 366 | |
| 367 | /** |
| 368 | * Increment tab level with following symbols. |
| 369 | * |
| 370 | * @param symbols Symbols to tab width. Length should be exactly 2 characters! |
| 371 | */ |
| 372 | public final void pushLevel(final String symbols) { |
| 373 | spaces.append(symbols); |
| 374 | } |
| 375 | |
| 376 | /** |
| 377 | * Set current tab level to current level. Might change unwritten lines. |
| 378 | */ |
| 379 | public final void setTabLevel() { |
| 380 | spacesForCurrentLine = spaces.toString(); |
| 381 | } |
| 382 | |
| 383 | /** |
| 384 | * Set number of maximum columns. If possible we break before we reach this column number. |
| 385 | * If less or equal to zero no line breaking is done automatically. |
| 386 | * |
| 387 | * @param columns Maximum column size. |
| 388 | */ |
| 389 | public void setColumns(final int columns) { |
| 390 | if (columns < 0) { |
| 391 | breakAt = 0; |
| 392 | } else { |
| 393 | breakAt = columns; |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * Return number of maximum columns. If equal to zero no line breaking is done automatically. |
| 399 | * |
| 400 | * @return Maximum column size. |
| 401 | */ |
| 402 | public final int getColumns() { |
| 403 | return breakAt; |
| 404 | } |
| 405 | |
| 406 | /** |
| 407 | * Append tabulation and increase current column. |
| 408 | */ |
| 409 | private void appendSpaces() { |
| 410 | append(spacesForCurrentLine.toString()); |
| 411 | col += spacesForCurrentLine.length(); |
| 412 | } |
| 413 | |
| 414 | } |